| 摘要 |
PURPOSE:To obtain an organic pigment having high tinting power and versatility, by dry grinding a crude organic pigment and an inorganic salt that will generate a gas by addition of an inorganic acid, treating the ground material with a crystallization solvent (an aqueous emulsion) and then adding an inorganic acid thereto for further treatment. CONSTITUTION:A crude organic pigment (e.g., a crude copper phthalocyanine) is dry ground together with an inorganic salt that will generate a gas by addition of an inorganic acid (e.g., sodium carbonate), the amount of the inorganic salt being 0.5-800wt% based on this pigment, and a chemical (e.g., calcium stearate) added if required for preventing the agglomeration of the organic pigment. The ground material is dispersed in a crystallization solvent (e.g., toluene or nitrobenzene) or an aqueous emulsion of this solvent to be treated therewith. An inorganic acid (e.g., hydrochloric acid) is added to this dispersion to decompose the inorganic salt to generate a gas (e.g., carbon dioxide gas) therefrom for further treatment. The treated material is separated by filtration, washed with water, and dried to give an objective pigment.
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